Updated November 14, 2014: One of the most popular posts I have ever published at ZDNet was that one, originally titled Seven perfectly legal methods for getting Windows 7 cheap (or even free). I wrote it at the end of 2009, and posted a follow-up 12 months later. If you have followed my advice, you could have saved large sums of money on upgrades and deals for students and IT pros.

5 years later, Windows 7 influences rear-view mirror. A lot of the deals classified by those original posts are no longer available. But it's indeed still easy to find cheap deals on PCs running Windows 7, once you learn where to look. It's also possible to tweak and tune newer Windows versions so they are functionally equivalent to Windows 7.

In that spirit, I've completely reworked this article with information that reflects the current PC market. [Last updated November 14, 2014]

Windows 7 is officially middle-aged. It had been publicly released over five years ago, on October 22, 2009. Each and every passing day it's getting further and further through the midpoint of Microsoft's 10-year support lifecycle for Windows releases.

In January 2015, Microsoft is scheduled to absolve mainstream support for Windows 7, and the five-year extended support phase will begin. In January 2020, the Windows 7 support lifecycle will officially end.

But 5 years is a long, while, and if you prefer the familiar environment of Windows 7 over its successors, you have still got lots of options available.

In case you navigate on your path through the confusing maze of Windows licensing rules, visitors the best deals head to PC manufacturers, this means you'll find the most effective new and refurbished PCs with Windows 7 preinstalled and ready to run.

If you just need the software, you can still cheap windows 7 professional in shrink-wrapped retail and OEM packages, sometimes at prices which can be literally too helpful to be true. If you are an IT pro or developer who needs Windows 7 for testing, you need to subscription options, although they're a smaller deal compared to they were 5 years ago. For students, the top options feature newer versions of Windows.

Almost all of the details I include in this post affect Windows customers in the United States, but you should be able to find similar offers in other countries.

My goal in this post is to give you deals that customers legitimately qualify for. I'm not really trying to encourage attempts by anyone to get away with something you aren't entitled to. If there are restrictions for a particular offer, I've noted them here.

Willing to get started? Pick a category and go... Old software on new PCs

Definitely the best way to buy Windows 7 today, 5yrs into its lifecycle, is to purchase it preinstalled over a new PC. You recruit a warranty and, more importantly, you get the OEM's assurance that this hardware and software specified to work together. This option also spares you the pain of Windows setup, particularly the hassles of seeking out essential drivers and system-specific updates when you upgrade (or downgrade) some type of computer.

New brand-name PCs with Windows 7 preinstalled

Yes, big-name PC makers could install Windows 7 on new PCs. You will find there's catch, though: By October 31, 2014 , any new PCs they have must include the more expensive Windows 7 Professional. Machines that have been manufactured before that date with Windows 7 Home Premium can nonetheless be sold.

The key in shopping for treadmills is to skip leading door and go straight for the business section. Among online merchants, for example, Dell offers filters to exhibit all available desktops and all-in-ones and laptops running Windows 7. HP gets the same options for desktops and laptops. When I checked a short while ago, HP had more Windows 7 options for business desktop PCs than all the operating systems combined.